OPEN Research Support

Colorectal Surgeon
Karam Matlub Sørensen
Department of Surgical Gastroenterology, Odense University Hospital

Projekt styring
Projekt status    Sampling ongoing
Data indsamlingsdatoer
Start 01.07.2015  
Slut 30.06.2020  

Anorectal abscesses and complex fistula-in-ano

Short summary

It is a PhD project, dealing with the issue of perianal sepsis. It includes three sub-projects, which are designed to evaluate three different aspects of the subject. The first part is a RCT to evaluate the outcomes of aspiration and antibiotics treatment vs. surgical drainage of perianal abscesses and the risk factors that might have a role in developing subsequent fistula. The second part is also RCT to evaluate the outcomes of Video Assisted Anal Fistula Treatment (VAAFT) vs. fistulectomy and sphincter reconstruction in terms of recurrence, functional results and quality of life changes. The last part is a pilot study to evaluate stem cells therapy for complex Crohns anal fistulas.


Anorectal abscess is a common condition, caused by cryptoglandular polymicrobial infection that can be adequately treated with simple surgical drainage. Anorectal abscess is associated with recurrence rates up to 44 % after surgical drainage and persistent subsequent fistula up to 37 %. Surgical drainage is associated with discomfort from prolonged wound healing, affecting the daily activities as well as the potential risk of complicated scaring and fecal incontinence. Less invasive method with needle aspiration of pus from the abscess under the cover with antibiotics has shown to be safe in terms of recurrence rate and subsequent fistula formation and well tolerated by the patients with less morbidity and wound complications and a potential lower risk of fecal incontinence. The first part of this study will be performed as a randomized controlled trial to evaluate the outcome of treatment of perianal abscess by needle aspiration and antibiotics compared to conventional incision.

Anal fistula presents the chronic form of anorectal sepsis and can be a manifestation of anal Crohn's disease. 25% of patients with anorectal abscess end up with a complex fistula. The surgical treatment of complex fistulas is difficult and ideally aims to completely heal the fistula and prevent recurrence without affecting the anal sphincter function. There are few RCTs in the literature on the treatment of complex anal fistulas treatment and there is no conclusive evidence of which method is the best . Furthermore, the knowledge of changes in quality of life and functional results in terms of standardized continence evaluation and manometric studies are either contradictive or simply lacking after the surgery for anal fistulas.  The aim of this second part of the study is to conduct a randomized clinical trial to compare VAAFT (mini invasive and sphincter-saving) with the traditional transsphincteric fistulectomy and primary reconstruction in terms of recurrence rate, manometric and functional changes as well as changes in quality of life.

Stem cells therapy has been recently applied in the treatment of complex anal fistula. It has been shown to be safe and feasible with encouraging short-term results both for cryptoglandular and Crohns anal fistula. The long -term results are not that encouraging but there are only few studies conducted with small patient series and various techniques and type of stem cells. This part of the study will be in cooperation with the new center of Regenerative Medicine in OUH. The aim of this project is to develop a method for treatment of patients with Crohns fistula. Crohn's patients are chosen because the results of conventional surgery in these patients are disappointing and followed by a high degree of recurrence and complications.

Description of the cohort

Perianal abscess treatment: it will include patients with acute visible perianal abscess, who are 18 years old and above.

Anal fistula treatment: it will include patients with complex anal fistulas, who are 18 years old and above.

Stem cells therapy study: it will include patients with anal fistulas caused by Crohn's disease, who are 18 years old and above.

Data and biological material

Through the three parts of the project clinical and radiological data will be collected. Wexner score for anal incontinence, St. Mark's fistula scheme, SF-36 sheets will be used.

Collaborating researchers and departments

Department of Surgical Gastroenterology, Odense University Hospital

  • Colorectal Surgeon and PhD-student Karam Matlub Sørensen
  • Professor Niels Qvist